The present invention relates to rotary regenerative heat exchangers and more particularly to the configuration of the main support pedestal panels and remaining panels for the heat exchange housing so as to accommodate the same configuration connecting duct assemblies on both hot and cold ends of the heat exchange.
A rotary regenerative heat exchanger, conventionally used as an air preheater for combustion equipment, is composed of a rotor, containing heat exchange surface, which is mounted on a vertical shaft for rotation within a heat exchanger housing which surrounds the rotor. Extending across the heat exchanger on the lower end below the housing, normally the cold end, is a cold end center section which serves as a support for the entire heat exchanger structure including the rotor. Because the center section is required to rotatably support a very heavy rotor, it is of a significant vertical height. Extending across the top of the heat exchanger, above the housing and parallel to the cold end center section, is a hot end center section. This hot end center section functions as the mounting means for the upper end of the rotor shaft. Because the hot end center section need only support its' own weight, the height of the hot end center section is less than the height of the cold end center section by a factor of 2 or 3. The hot end center section is supported by main support pedestals on each end of the hot end center section which are, in turn, supported on the ends of the cold end center section.
The main support pedestal panels on each end of the hot and cold center sections form a part of the heat exchanger housing. The remainder of the housing comprises a plurality of housing panels arranged around the periphery of the rotor. Typically, there are eight or more sides including the main support pedestal panels and the remaining housing panels. Mounted on the inside of each housing panel including the main support pedestal panel between the panels and the rotor are arch-shaped stiffeners which cooperate to form a close fitting circular flange around the rotor. Conventional bypass sealing means are provided between the rotor and these arch-shaped stiffeners to prevent the by-pass of air or flue gas around the outside of the rotor.
Attached to each end of the heat exchanger housing are the air and gas connecting plate duct assemblies. These are connections which make the transition between the duct work, which is usually rectangular, and the circular heat exchanger and are attached to the sides of the hot and cold center sections. The housing panels are attached to and between these connecting plate duct assemblies thereby forming the housing.
The conventional arrangement is for the hot end connecting plate duct assemblies to be of a height equal, to the height of the hot end center section and for the cold end connecting plate duct assemblies to be of a height equal to the height of the cold end center section. In this arrangement, all of the housing panels including the main support pedestal panels are of the same height. Since the hot end center section and the cold end center section are of different heights, the height of the hot and cold end connecting plate duct assemblies are also different. This means that two different connecting plate duct assemblies must be designed and manufactured thereby increasing the costs. Also, the cold end connecting plate duct assemblies are significantly larger and more difficult to assemble and handle.